This audio story is brought to you by BirdNote, a partner of the National Audubon Society. BirdNote episodes air daily on public radio stations nationwide.

Transcript:

Some birds are just misunderstood and have been for centuries. Take the Eared Grebe, for example. The earliest description in the North American literature—dating from 1577 and based on Aztec observations—notes, “Its food is its feathers, only sometimes it eats fish.”

Strange as it sounds, grebes do indeed eat their own feathers. Eared Grebes eat mainly brine shrimp and aquatic insects, which have rigid exoskeletons, making them both tough to digest and potentially damaging to the intestines.

So, grebes evolved to use their feathers as a way to slow down digestion. After the bird swallows them, the feathers enter a three-part stomach — first a storage chamber, then a gizzard, and lastly a pouch. The feathers form dense balls in both the gizzard and final pouch and appear to slow the passage of food long enough that the food can be safely liquified.

The tough bits are then regurgitated within a ball of feathers, much the way owls spit up pellets of bones from their prey. A grebe may pop out as many as six feather balls in an evening.

For BirdNote, I’m Michael Stein.

***

Credits: 

Written by: Bob Sundstrom 

Narrator: Michael Stein

Senior Producer: John Kessler

Production Manager: Allison Wilson

Editor: Ashley Ahearn

Producer: Mark Bramhill

Associate Producer: Ellen Blackstone

Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Eared Grebe call, ML106819, recorded by Randolph Little. ML133198 recorded by Gregory Budney. 

BirdNote’s theme was composed and played by Nancy Rumbel and John Kessler.

© 2021 BirdNote   January 2021    

ID#  grebe-01-2021-01-15           grebe-01

Stay abreast of Audubon

Our email newsletter shares the latest programs and initiatives.